It is customary to mount a pump or compressor between the walking beam and a stationary portion of a pump jack for a downhole pumping unit. Among other problems associated with such systems is the side loading imparted by the walking beam through the pump or compressor and particularly at the connecting ends which can impart a great deal of stress or strain to the working elements of the pump or compressor. A somewhat associated problem has to do with the manner of connection of each end of the pump or compressor between the walking beam and stationary portion, such as, the leg of a samson post and which in the past has required some form of permanent connection, such as, by welding or bolted connections through openings in the connecting members.
Representative of the systems which have been employed in the past is that disclosed in U.S. Pat. No. 4,530,646 to C. D. McCoy in which swiveled connections are utilized for mounting the compressor to a walking beam and lower samson post as well as to permit lengthwise adjustment to vary the support point for the lower end of the piston rod to the samson post; however, in McCoy, the swivel axes are arranged at right angles to one another in an effort to compensate for any misalignment and requires direct bolted attachment to the walking beam and samson post. In U.S. Pat. No. 3,665,301 to C. F. McClung, swivel connections are provided at opposite ends of the compressor which are broadly described as being in the form of knuckle joints, and a buckle type of adjuster is utilized between the lower end of a cylinder and a lower swivel joint. U.S. Pat. No. 4,345,734 to J. Studinger discloses a telescoping inner and outer post arrangement for a walking beam compressor. Other representative patents are U.S. Pat. Nos. 1,775,773 to J. T. Phipps, 2,113,562 to R. C. Mason and 4,557,351 to R. D. Volk.
There continues to be a need for a novel and improved form of connection between the pump or compressor and connecting ends on the pumping unit so that any side loading or lateral displacement can be most effectively absorbed through the connecting ends and at the same time avoid the necessity of lubrication of the bearings; also, to avoid the necessity of any permanent or positive attachment at the connecting ends.